The overall objective of this project is to identify the sequence of intracellular reactions which lead to the formation of hydrochloric acid by gastric mucosa and to identify the major controlling steps in this sequence. The project involves use of a combination of non-destructive optical techniques, conventional biochemical analysis and electron microscopy to investigate receptor mechanisms, cyclic nucleotide metabolism, energy metabolism and morphological changes as these parameters are modified during transitions of acid secretory state. The studies are performed on isolated intact gastric mucosa and isolated gastric cells. The goal of the project is to integrate these measurements so as to provide a more comprehensive view of the cellular events associated with acid formation.